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प्रश्न
State two properties that a substance should possess when used as a thermionic emitter.
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उत्तर
Two properties are:
(i) High melting point. (ii) Low work function.
संबंधित प्रश्न
Arrange α, β, and γ rays in ascending order with respect to their
1) Penetrating power.
2) Ionising power
3) Biological effect
What happens if the negative potential is changed on a grid?
What is thermionic emission?
An electromagnetic radiation is used for photography in fog. [2]
(i) Identify the radiation.
(ii) Why is this radiation mentioned by you, ideal for this purpose ?
What do you mean by Mass number.
State three safety precautions that you would take while handling the radioactive substances.
Define bound electrons.
How is a zinc sulphide screen affected when a cathode ray beam strikes it?
Which of the following statements is/are correct?
- α particles are photons
- Penetrating power of γ radiation is very low
- Ionization power is maximum for α rays
- Penetrating power of γ radiation is very high
If 10% of a radioactive substance decays in every 5 years, then the percentage of the substance that will have decayed in 20 years will be ______.
